1. Field of the Invention
The present invention relates generally to apparatuses and methods for simulating submarine landslides and, more particularly, to an apparatus and method for simulating a submarine landslide or a debris flow which is caused in an actual seabed by dissociation of gas hydrate or an earthquake.
2. Description of the Related Art
A submarine landslide is a generic term for landslides that occur in submarine environments. Submarine landslides include activity (slides) or diffusion of a seabed, rockslides, debris flow, etc. Such submarine landslides occur in a variety of submarine environments, for example, in a continental shelf slope and rise, a sea loch or lake, a submarine canyon, an inland sea, an estuary, a delta, a volcanic island, etc. Submarine landslides are mainly caused by earthquakes, dissociation of gas hydrate, an unconsolidated layer being formed during a sedimentary layer forming process, subsurface water penetration, abrupt sea level variation, etc. In the deep sea, dissociation of gas hydrate and earthquakes are responsible for the majority of submarine landslide occurrences.
Compared to landslides on land, the occurrence scale and damage degree of submarine landslides are relatively large, thus posing a severe danger to humans. In the same manner as a landslide on land, a variety of causes may trigger a slide (land activity) in an unstable seabed and markedly reduce shearing strength which affects the ground stability. Collapsed submarine landslide substances create debris flow which flows downwards in a fluidized form.
The scales and travel distances of submarine landslides are about 100 to 1000 times those of landslides on land. Therefore, damage, which is caused by water waves resulting from a submarine landslide, and impact force, which is applied to the coastal area by submarine debris flow, are also very large. Furthermore, if methane gas produced by natural or artificial dissociation of gas hydrate is released from a deep seabed into the atmosphere without being burned, a serious greenhouse effect that is about 20 times more damaging than that of released carbon dioxide may be caused. In addition, during a process of drilling for gas hydrate, which is a natural energy source, a seabed in which gas hydrate is present is disturbed, thus making a deep sea stratum unstable. Thereby, a geological disaster may be caused.
An apparatus for simulating a landslide was proposed in Korean Patent Application No. 10-2008-0066805. This apparatus can measure the possibility of the occurrence of a landslide on the ground and the range and size of damage caused by the landslide. However, the testing apparatus is problematic in that it cannot simulate a submarine landslide.
Given this, a separate apparatus, which can simulate a submarine landslide caused by dissociation of gas hydrate or an earthquake and easily measure the scale the submarine landslide, the mobility of debris flow, a debris flow deposition pattern, heights and speed of water waves (for example, a tsunami), is required.